Improvement in devices for leveling the key-frames of piano-fortes



O. F. T. STEINWAYA Device for Leveling Key-Frames of Piano-Fortes,

No. 217.828. Patented July 22,1879.

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UNITED STATES PATENT OFFICE.

CHRISTIAN F. T. STEINYVAY, OF NEW? YORK, N. Y.

IMPROVEMENT IN DEVICES FOR LEVELING THE KEY-FRAMES 0F PlANO-FOR-TES.

Specification forming part of Letters Patent No. 217,828, dated July 22,1879; application filed May 14, 1879.

To all whom it may concern:

Be it known that I, OuRisTmN Fmnnnrcn Tnnonou STEINWAY, of the city,county, and State of New York, have invented a new and usefulImprovement in Devices for Leveling and Regulating the KeyFrames ofPiano-Fortes, which improvement is fully set forth in the followingspecification, reference being had to the accompanying drawings, inwhich Figure 1 represents a vertical section of a key=l:'rame containingmy invention, the plane of section being indicated by the linea 00, Fig.2. Fig. 2 is a similar section in the plane of the line y y, Fig. 1.

Similar letters indicate corresponding parts.

The object of my invention is to produce a simple and effective devicefor leveling, regulating, or controlling the position of the keyframe ina piano-forte, and especially that part of such frame called thebalancerail.

Prior to my invention the bottom frame of a piano formed the rest orfoundation of the key-frame, and, inasmuch as by the character of apiano-action it was necessary to plane or face these two frames with theutmost accuracy, much labor was involved in perfecting the same, whileat the same time the least warping of either frame caused by the dryingor swelling of the wood influenced or changed the level of thekey-frame. This change affected the key-frame mostly at the balancerail,constituting the fulera of the keys, and hence changed or spoiled thetouch of the ac tion.

My invention, bcingapplicable alike to grand, square, and uprightpianos, consists in combining with the bottom frame or support of thekey-frame one or more metallic disks having a screw-threaded leg,adapted to be turned by means of a wrench or otherwise so that thekey-frame rests directly on the disk or disks, and by simply adjustingthe latter the level of such frame can be changed and controlled.

In the example shown in the drawings, the letter A designates a portionof the bottom frame of a grand piano-forte, connected with thewrest-plank B by side pieces, one of which is shown at O, and D is aportion. of the keyframe, this latterbeing situated above or upon thebottom frame. This key-frame consists of from four to six base-rails, a,extending parallel with the keys, and of a balance-rail, 1), extendingtransversely to the base-rails and forming the fulcra of thekeys.

For the purpose of supporting the key-frame D on the bottom frame A, thelatter is equipped with a metallic disk or plate, E, or a number of suchdisks. This disk l is sunken into the top surface of the bottom frame A,and is preferably made convex, as shown, while upon the same is cast orotherwise formed a leg, (I, which is screw-threaded, and which projectsdownward through a threaded hole in the bottom frame A. On its lower endthe leg (I is made square, so that the same may receive a wrench ortuning-hammer for the purpose of turning the leg (I, thereby adjustingthe disk in a higher or lower position; and the leg (I terminates withinor above the lower surface of the bottom frame A, while the latter isprovided with a recess, 0, around the leg (I, to admit the wrench ortuning-hammer referred to.

The disk or disks E are placed in that part of the bottom frame A whichis in the line of the balance-rail Z) and beneath each base-rail a, sothat each base-rail rests directly upon its disk; hence by a properadjustment of this disk or disks E the level of the keyframe I), andparticularly that of the balance-rail, can be very readily adjusted andcontrolled to the greatest nicety.

In some cases it is desirable to reverse the position of the disks E, sothat they bear upon the bottom frame A, while their legs (I extend upthrough and screw into the balance-rail, as shown in Fig. 2. This changebecomes necessary near the ends of the key-frame, where the bottom framerests upon the legs of the piano-forte, so that the screwlegs d of thedisks E cannot be reached from below.

\Vhat I claim as new, and desire to secure by Letters Patent, is-

1. The combination, with the support of the key-frame in a piano-forte,of a metallic disk (one or more) having a screw-threaded leg, adapted tobe turned by means of a wrench, tuning-hammer, or otherwise, for thepurpose of directly leveling and regulating the keyand regulating thekey-frame, substantially as frame, and thereby simultaneously adjustingdescribed.

all the keys, substantially as described. In testimony that I claim theforegoing I I 2. Thecombination, with the support of the hereunto set myhand and seal this 29th day of f key-frame of a piano-forte and thebalance- April, 1879. I;

rail of the keys, of a metallic disk (one or: CHRISTIAN F. T. STEINWAY.[L.s.]

more) having a screw-threaded leg adapted to Witnesses:

be turned by means of a Wrench, tuning-ham- W. HAUFF, f

mer, or otherwise, for the purpose of leveling CHAS. WAHLERS.

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